It is well known that many power trains employ belts and pulleys for transferring power from one shaft to another, and that in the course of employing such systems it may become necessary to adjust the tension of the belt. The most frequent occurrence is that due to stretching of the belt or movement of the pulleys the belt becomes too loose to function properly and must be put under greater tension in order to provide enough friction not to slip on the pulley.
A modern type of belt-and-pulley combination is the V-belt and the corresponding sheave. These are widely used on automobiles to provide power transfer from the crankshaft of the engine to auxiliary equipment such as the waterpump, the generator, the aid conditioning compressor, etc. The auxiliary equipment is normally mounted on a pivotable frame to permit adjustment of the distance between sheaves to provide the proper belt tension. The usual difficulty is that of forcing the sheaves and V-belt far enough apart to obtain the proper belt tension and to hold the sheaves in the position long enough to clamp the auxiliary equipment holding the sheave in that position. It is an object of this invention to provide an apparatus for accomplishing this task with facility.
There have been known in the prior art devices for accomplishing this purpose. For example, U.S. Pat. Nos.,
U.S. Pat. No. 3,325,095 PA1 U.S. Pat. No. 3,679,176 PA1 U.S. Pat. No. 3,727,884 PA1 U.S. Pat. No. 3,869,934 PA1 U.S. Pat. No. 3,920,219 PA1 U.S. Pat. No. 4,036,029
all describe apparatus to tighten belts on pulleys. Some of these function by being mounted between cooperating sheaves and pushing them apart by the force exerted by advancing a screw thread. Many of these latter types have sharp blade-like members at each end to engage the V-groove in the sheaves. The adjustment of the screw thread is usually accomplished by turning a nut in the middle of the device somewhat like a turnbuckle. This is not convenient for automobile engines where little space is provided for hands to repair the engine. Furthermore, there may be a much more convenient point of attachment to spread the sheaves apart than the bottom of the V-groove.
It is an object of this invention to provide an improved apparatus for tightening belt drives. It is another object to provide such an apparatus that may be adjusted to provide many operating positions for more convenience. Other objects will appear in the more detailed description which follows: